Current transformer saturation discrimination method and device suitable for 3/2 wiring circuit

Abstract

The invention relates to a current transformer saturation discrimination method and device suitable for a 3 / 2 wiring circuit. The method comprises the following steps: firstly, acquiring current sampling values of a middle circuit breaker and a middle circuit breaker in a circuit in one cycle; calculating the current correlation and harmonic coefficient increment of the side circuit breaker and the middle circuit breaker according to the current sampling value; and comparing the current correlation and the harmonic coefficient increment with respective threshold values, and when any one of the current correlation and the harmonic coefficient increment exceeds the threshold value, judging that the current transformer is saturated. According to the technical scheme provided by the invention, the saturation of the current transformer is judged by judging whether the current correlation and the harmonic coefficient increment exceed the threshold range or not, when any one of the side circuit breakers and the middle circuit breakers is saturated, the saturation state of the current transformer can be identified in time, protection misoperation caused by saturation of the current transformer is effectively avoided, and the safety of a power grid is improved.

Description

technical field [0001] The invention relates to the technical field of power system fault detection, in particular to a current transformer saturation discrimination method and device suitable for 3 / 2 wiring lines. Background technique [0002] The current transformer is an important secondary measurement equipment in the power system. Its normal operation is directly related to the safety of the power system. It has occurred many times in the field that the primary current is too large to cause CT saturation, resulting in secondary current distortion, and finally a protection leapfrog tripping accident. For the short-lead protection and line longitudinal differential protection applicable to 3 / 2 circuit breaker wiring, when an out-of-area fault causes CT saturation, if the CT saturation state cannot be identified in time, it will lead to short-lead protection and line longitudinal differential protection. The malfunction of the automatic protection will seriously affect th...

AI Technical Summary

Problems solved by technology

[0002] The current transformer is an important secondary measurement equipment in the power system. Its normal operation is directly related to the safety of the power system. It has occurred many times in the field that the primary current is too large to cause CT saturation, resulting in secondary current distortion, and finally a protection leapfrog tripping accident

For the short-lead protection and line longitudinal differential protection applicable to 3 / 2 circuit breaker wiring, when an out-of-area fault causes CT saturation, if the CT saturation state cannot be identified in time, it will lead to short-lead protection and line longitudinal differential protection. Malfunction of automatic protection will seriously affect the safety and stability of power grid

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